Lamp socket for photoflash units



Aug. 19, 1958 E. s. MGKE ETAL 2,848,701

LAMP SOCKET FOR PHOTOFLASH UNITS Y Filed May 18, 1956 'IKL-TI.. 42 4 infn Edward ,S MCKQ e WmundFDe/fwbalyh 1N VEN TORS l'United States Patent G LAMPv SOCKET Anon\Pnoiortasn UNITS Edward S. McKee andiEdmund F. Detenbaugh, Rochester, N. Y., asslgnors to Eastman Kodak Company, Rochester, N. Y., a corporation f Newl'ersey Application May 18, 1956, Serial No. 585,750 2 Claims. (C l. 339?45) The present invention relates to photoash units for cameras and particularly to a dual lamp socket for such photoash units which is adapted tointerchangeably and releasably seaty different types of conventional ilashlarnps, i. e., a lamp having -a small diameter base and having a circumferential groove therein (M-Z ashlamp) or aV lamp having a larger diameter base and having bayonet pins extending radially therefrom and l#25 flashlamps).

The irst small size ashlamps, i. e. #-5, #25, SM, etc., had a base provided with two d iametrically spaced bayonet pins which served both as a means of locking the lamp in its socket and asa means of connecting'one end of its filament to one side of a power source when the lamp is inserted into a socket. Then the now wellknown midget ashlamp, i. e., the M-2l was introduced which has a base whose diameter is smaller than the base of the #5 and is provided with a circumferential groove in the base ratherthan bayonet pins. In order to adapt photoilash units for both of these types of lamps, the photoflash unit socket has been designed to normally accommodate the larger #5 lamp and then an adapter has been provided for this socket which would permit the use of the smaller M-2 lamps. This means that the photographer must remember to carry this adapter with him and insert it into the photoash unit socket whenever he wants to use M-Z lamps.

The primary object of the present invention is to provide a dual lamp socket for a photoiash unit which permits the photographer to insert either a #5 or #25 flashlamp (large base) or an M-2. lamp (small base) into the socket without the inconventience of removing or replacing an adapter.

The novel features that we consider characteristic .of our invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof, will best be understood from the following description when read in connection with the accompanying drawings, in which:

Fig. l is a rear elevational view of a photoash unit with the cover removed and incorporating a dual lamp socket constructed in accordance with a preferred embodiment of the present invention;

Fig. 2 is a side view of the photoilas'h unit with the socket portion shown in section and taken substantially on line 2-2 of Fig. 1;

Fig. 3 is a sectional detail of the lamp socket taken substantially on line 3 3 of Fig. l and showing an M-2 flashlamp in place therein;

Fig. 4 is a sectional View similar to Fig. 3 with no n..

2,848,701 Patented Aug. 19, 1958 2. position and is held in this position by a coiled spring when an M-2 lamp is inserted into the' socket. The inside diameter offthis sleeve fits the outside diameter ofk the M-2 lamp base and acts as a socket for locating the lar'npcentrally. of the reector. When a #5 or #25 flashlamp (with a larger diameter base) is inserted-into a socket, the lamp base forces kthe retractable sleeve rearwardly againstthe coil spring pressure until'the lamp is locked in position. Both types of lamps arelatched in properV position in the socket 'by a common releasable latchin'g: member which also connects the lamp filament to onel side of a source of power in the photoilashl unit. rneretractable sleeve is guided in its travel by a central pilot tube which in turn guides a spring loaded central contact which is engaged and retracted by the center contact of each type'of lamp as it is'insertedV into( the socket. i

Referring now to the drawings, the photoash unit of` which, the socket of the present invention formsa part comprises a housing 16 ofthe shape best 'shown in Pig. l which is adapted to contain alll of the electrical components and be molded from a plastic material for insulation purposes. The" rear ofy the housing has a removable metal cover 131 which lis held in place by a screw 12, said cover being removed to change two batteries B lying in side-by-side relation and which may constitute the power source for firing the lamps.

As is customary in the art, this photoilashunit is adapted to be detachably connected to the side wall'o'f a camera and be electrically connected'into the flash synchronizing switch controlled by the camera shutter. To this end the photoilash unit includes lt'ncating pins 13 and 14 plus lan attaching screw 15' which'engage corresponding holes in the wall of a camera'. Each of pins 13l and 14 merely slidably engage locating holes in the camera body while attaching screw 15 engages a threaded bore in the camera body to draw the photofla'sh unit down tightly against Athe camera and force the pins 13 and 14 Acon'ipl'etely into their respective holes. Attaching screw 15 and pin 14l form parts of the electrical circuit between the ash switch in the camera and the photoash unit components, whereas pin 13 is merely a locating pin and formsl no part of the electrical' circuit. 'Piri`14' has apress tit with end 17 of a metal contact strap 18 which is bent upV and over a pair of spaced insulating' partitions 19 bearing four l`upstandingposts 20 for positioning the strap laterally. "lf the power source consists `of two No.2 batteries B adapted to be placed in -the'ph'otoflash unit in side-by-side 'relation and with bot'rivba'ses downward, lthe end ofcontactV strap 18 is tnrneddown to engage and support the bas/e of the innermost battery. The" top contact of this innermost battery and the bottom contact of the outermost battery are electrically connected byv anV offset lmetal Contact strap 21"which isrfast'ened tothe side wallof the 'photoiiash unity by locating pin'13. The top contact'of the' outermost battery B isy engaged bythe turned-up end 22 of a contact strap 23 which 'has a turned-'overV ear 24 adapted to be electrically connected by a Vscrew 25 to a metal bracket cover 26 of the form best shown in Fig. l( I Tl'iedmetal bracketvcover 26,y which serves'to' connect the center Contact of the lamp socket into the electrical 'circuit of the4 photoash unit, is located in the photofalling out of the cover plate when the same is removed from theshousing., The metalV bracket 26 also includes an arm 32 having a turned-down projection 33 behind is held while the other end 35 of the separator is positioned between the end 36 of an elongated metal contact and lamp ejector lever 37 and the ends of partitions 19.

AThis separator 34, along with the wall 38 of the photoash Yunit housing, defines the battery compartment.

,i The resilient metal contact lever 37 extends substantially Vthe full length of the photoash unit casing and serves as a partof a releasable latching means for locking the lamps in the socket as well as serving to electrically connect the lamps into the battery circuit. The lower end 36 of ejector lever 37 is forked and embraces attach- A shoulder 38 on the attaching screwing screw 15. is adapted to be drawn down tightly against the forked end of the lever 37 when the photoash unit is mounted on the camera body and thus produce a good electrical contact between screw and lever 37. The other end of lever 37 extends to the top of the photoilash unit and terminates in an end 39- which is normally urged radially toward the lamp socket to provide a lamp latching means as Vwill be described hereinafter.

Thedual lamp socket of the present invention is in the upper, offset and rounded end of the photoflash unit housing which is molded to form a hollow casing 40 provided with a circular lamp opening 41 bounded by a circular wall 42 whose diameter is just large enough to accommodate the circular base of a #5 or #25 flashlamp and locate such lamp in a correct position relative to the reflector R. As shown in Figs. 4 and 5, a conventional #5 and #25 ashlamp has a pair of diametrically which one'end ofva thin separator 34 of insulating materialY l spaced bayonet pins 43 extending radially from a large i diameter circular base 44 and a center contact 45. The conventional M-2 ashlamp, on the other hand, is considerably smaller than the #5 or #25 flashlamp and has a smaller diameter circular base 46, a central contact 47 and a circumferential groove 48 in its base instead of bayonet pins. While the reflector may be permanently attached to the photoash unit, we have shown a design wherein it is detachably connected thereto for permitting the use of different size or lshaped reflectors if desired. To this end, the front wall of the photoflash unit is provided with a pair of recesses 50 and 51 of dilerent depth which are concentric to each other and the lamp socket or opening 41. Mounted on the step 52 formed by these recesses is a bayonet-type latch ring 53 behind which bayonet lugs 54 on the rear of the reflector R are adapted to be hooked by a partial rotation of the reflector to fasten the reflector to the photoflash unit.

Slidably mounted within the opening 41 and guided by the wall 42 thereof is a retractable sleeve 56 made of an insulating material. a forwardposition by a coil spring 57, and the sleeve is limited in its outward movement by engagement of radial lugs 58 thereon which engage the end of wall 42. 'Ihe inside diameter of this retractable sleeve fits the outside diameter of the M-2 lamp base and acts as a socket for locating this smaller lamp centrally in the reflector, see Fig. 3. i

When a #5 or #25 fiashlamp (with larger base diameter) is inserted into the socket, the lamp base engages and forces the retractable sleeve rearwardly against the coil spring pressure until the lamp is locked in position, see Fig. 5. Since the circular opening 41 defined by wall 42 corresponds to the outside diameter of the base ofA the #5 or #25 ashlamp, the Ywall42is provided with a pair of diametrically disposed axial slots 60 which are deep enough to pass vthe bayonet pins on such lamps. These slots, J therefore, compel a proper orientation of This sleeve is normally urged to.

the #5 or #25 lamps for insertion into the socket so that the latch means to be described will properly engage the bayonet pins 43 to hold the #5 or #25 lamps in the socket.

The retractable sleeve 56 is guided in its travel b a vcentral pilot tube 61made of insulating material and vwhich is in turn laterally locatedin the casing by turned-up lugs 62 on the metal cover bracket 26. This pilot tube is in turn held against the metal cover bracket by the action of coil spring 5 7. Slidably mounted within this pilot tube is a metal center contact 63 which may be provided with a sharp point 64 adapted to cut into the center base contact 45 or 47 of #5 or M-2 lamps, respectively, to provide good electrical contact, see Figs. 3 and 5. The center contact 63. is normally urged forwardly of the socket by a coil spring 65 confined between the enlarged bottom thereof and the metal cover bracket 26, andr this spring 65 also -serves'to electrically connect the center contact to one side of the battery circuit through the metal cover bracket 26. Outward movement of center contact 63 is limited by an overhanging flange 66 on the end of the pilotV tube 61, see Fig. 4.

Both types of lamps are retained in proper position in the socket and connected into the battery circuit byY yitis pushedV into the socket with a straight thrust and positively latch the lamp` in the socket, see Fig. 3. The latching aperture 71 is located further forward relative to the socket and Yis adapted to engage one of the bayonet pins 43 on the base of a #5 or #25 lamp to latch the.

same in the socket, see Fig. 5. The extreme edge of the end 39 is ared outwardly as'V shown at 73 so that a ybayonet pin 43 on the #5 lamp can cam the end 39 of ejector lever 37 away fromy the socket and slide into Vlatched relation with the aperture 71.

Looking at Fig. l, it will be seen that ejector lever v37 is xed at its lower end 36 and is deformed at 72 so that the normal resiliency 0f the lever tends to movethe end 39 thereof, and the catch portion 70 and the latching aperture 71 thereon, radially toward the socket and into a lamp latching position, see Figs. 3 4and 5. To release a lamp from a socket, end 39l of ejector lever 37 is sprung away from the socket, or to the position shown in Fig. 4, where both the catch portion and the latching aperture 71 release the circumferential groove 48 of an M-2 lamp or the 'bayonet pin 43 of a #5 lamp, respectively. `This is accomplished from the outside of the photoflash unit by pressing inwardly on the end 75 of a plastic pin 76 which has a reduced end 77 engaging a hole in the ejector lever37. A flange 78 on pin 76 engages the inside face of the photoash unit wall to limit the outward movement of the pin and hence determine the normal position of ejector lever 37. Y Looking at Figs. l and 2, it will be seen that the ejector lever 37 is confined laterallyk by lying beneath the down-turned ear 2S on the metal cover bracket 26. Since each ofthese two parts is `connected into the battery circuit, to prevent short-circuiting the lamp socket a strip of insulation 8@ is placed between the underside of down-turned ear 28 and the ejector lever 37 Having thus described our invention, it is believed that it will Ibe apparent that the disclosed dual lamp socket for liashlarnps provides a fairly simple socket arrangement which can readily accommodate either M or #5 and #25 type flashlamps despite the fact that each `of these types of ashlamps-has a different size base and different means for latching ,the lampsin the socket.

This dual socket is so designed that either type of flashlamp mentioned canbe inserted thereinto by a straight thrust and each lamp will le positively latehed in the socket in proper relation relative to the reflector surrounding the same. The latching means for each lamp not only serves to properly connect the respective lamps into the battery circuit, but is so designed that the lamp latching means for both types of lamps can be operated by a single release button on the outside of the photoash unit. The design of this socket also is conducive t0 easy assembly since no soldered or wire connections yare used. While we have shown our novel dual lamp socket in connection with a particular type of photoflash unit, it is pointed out that its use is not limited to such a photoash unit 'but ythat it can be used equally well on photoflash units having different types of power sources than that disclosed and on photoash units which are used separate from the camera and electrically connected to the ilash synchronizer switch associated with the camera shutter through the use of separate wire leads rather than being mounted directly on the camera body Iand electrically connected to the synchronizer switch by means of such mounting.

Although We have shown and described certain specie embodiments of our invention, we are fully aware that certain modifications thereof are possible. Our invention, therefore, is not to be limited to the precise details of construction shown and described but is intended to cover all modications coming within the scope of the appended claims.

Having thusdescribed our invention, what we claim as new and desire to secure by Letters Patent of the United States is:

1. A dual lamp socket for a photoash unit adapted to releasably seat interchangeably regular ashlamps having a lbase from which bayonet pins extend radially and midget flashlamps having a base of smaller diameter than said regular lamps and having a radial ange extending circumferentially thereof and connect them in circuit with a power source carried by the photoash unit and comprising in combination a hollow casing provided with a circular opening into which the lamp bases are adapted to be inserted and having an internal diameter slightly larger than the exterior diameter of the base of a regular lamp, diametrically disposed radial slots in the Wall forming said opening adapted to pass the bayonet the center contact of any lamp inserted into the socket,

a coiled spring normally urging said center Contact to an extended position and serving to electrically connect said contact to one side of the power source, Cooperat- 1.: ing means on said center contact and said pilot sleeve limiting the outward movement of said contact, a retractable sleeve slidably mounted on the exterior of said pilot sleeve and having an internal diameter slightly larger than the outside diameter of the base of a midget lamp, whereby it is adapted to act as a socket therefor, and having an external diameter substantially equal to the diameter of the base of a regular lamp, a coiled spring normally urging said retractable sleeve to `an extended position, cooperating lugs on said retractable sleeve and said casing limiting the outward movement of said sleeve to said extended position, and a single releasable metal latch member within said casing adapted to positively engage a bayonet pin on the base of a regular lamp and the radial flange on the base of a midget ashlamp when one or the other type of lamps is pushed into said socket with a straight thrust to latch the lamp in said socket and at the same time connect the lamp base to the other side of said power source in the photoflash unit.

2. A dual lamp socket for a photoash unit according to claim l in which the wall of said retractable sleeve is provided with an axial slot aligned with one of the radial slots in the wall of said opening, and in which said releasable latch member includes a projection normally extending radially into said axial slot in said sleeve to positively engage said radial flange on the base of a midget lamp when the same is inserted into said socket and includes a catch member normally extending axially of the exterior of said sleeve to positively engage one of the bayonet pins on the base of a regular lamp when it is inserted into said socket, and means extending to the outside of said casing` to move said release member radially from its normal position relative to said retractable sleeve to move said projection and catch from their latching positions.

No references cited. 

